The potential of stable isotopes of water for process analysis and modeling in cryosphere-dominated environments

Streamflow generation in cryosphere-dominated environments results from the complex interplay of precipitation accumulation and release processes across spatial and temporal scales. While the general streamflow dynamics of such environments are very well understood and relatively easy to simulate, the actual underlying storage-release processes are more difficult to reliably represent in models than what is currently thought.  Using stable isotopes of water to trace hydrological flow paths, estimate water age or attribute streamflow sources has become standard in hydrological process research. The isotopic ratios of oxygen or hydrogen in rainfall and snowfall commonly show substantial differences in alpine environments. Accordingly, it is tempting to think that they represent an ideal tracer to quantify the hydrologic partitioning at various time scales (from the event scale to the seasonal scale) and across a range of processes (ice melt, snow melt, rain-on-snow, infiltration, groundwater recharge, vegetation water uptake, baseflow generation). In this contribution, we discuss the potential of isotope analyses for cryosphere-dominated catchments regarding process research and modeling, what essential insights we can derive from stable isotopes of water for downstream water resources management under a changing climate, and we provide recommendations for future sampling campaigns.